Kidney disease in cats: What you need to know

On Friday we talked about the newly discovered cat virus, feline morbillivirus, that may have a link to tubulointerstitial nephritis, a potentially fatal inflammation in a cat’s kidneys, and what the finding means for cat parents. We talked with Pawcurious blogger Dr. V to learn more about tubulointerstitial nephritis in cats, its diagnosis and treatment.

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PETFINDER: What is tubulointerstitial nephritis in cats?

DR: V.: Nephritis in the general sense refers to kidney inflammation. The kidney
is made up of units called nephrons. Each nephron is comprised of a
glomerulus and a tubule. “Tubulointerstitial” localizes the
inflammation to a specific part of the kidney — the tubules and the
surrounding matrix.

What are its symptoms?

The symptoms of kidney disease are pretty widespread. The most common
signs owners first notice are increased thirst and increased urination.
As the kidneys are unable to properly concentrate urine, water just
passes right on through and the cat attempts to keep up with this loss
by increasing his fluid intake. As the disease progresses, we often
see nausea, weight loss, vomiting and bad breath. [Learn more about the symptoms of kidney failure in cats.]

After the jump: How kidney disease in cats is diagnosed and treated.

How do you diagnose it?

Your vet makes an initial diagnosis of renal disease usually
based on blood work, urinalysis and physical examination. She can
further refine
the diagnosis through additional testing. A specific diagnosis of
tubulointerstitial nephritis requires an examination of a section of
tissue by a pathologist, and even then it tells you what part of the
kidney is damaged but not necessarily why it’s damaged.

What are the steps to prevent it?

Since there are so many causes of kidney disease, it’s hard to pinpoint a
way to prevent it. The kidney is susceptible to lots of insult, from
toxins to infections, autoimmune disease, genetic problems — you name it.
Some people suggest diet is a factor, and others suggest dental disease
may contribute. The main point to remember is this: No matter the
cause, early detection is key. The sooner renal disease is diagnosed,
the better chance you have of managing its progression.

What is the prognosis and treatment for it?

In acute renal disease, if you can get the cat over the initial crisis
they can sometimes have a full recovery. If the renal failure is the
result of a chronic, long-term loss of kidney function, you are looking
at an irreversible condition. [Learn more about acute vs. chronic kidney failure in cats.]

Since the kidney is also involved with
blood pressure and blood-cell production, as the kidneys fail we can
also see signs of hypertension [high blood pressure] and anemia [having a low number of red blood cells].

Long-term
management involves
keeping the pet hydrated and staying on top of all the other problems
that develop, keeping the pet eating, managing anemia and hypertension
and trying to minimize the effects of elevated blood waste. [The kidneys
filter out bodily waste, so poorly-functioning kidneys can increase
waste in the blood.] Some cats
have undergone dialysis and kidney transplants as well, though this is
much less common.

Chronic renal failure is a terminal condition, and the goal of treatment
is not eliminating the disease, but slowing down its progression and keeping
the quality of life good as long as possible [which can mean weeks, months or years].

How often does it occur or do you see it in your practice?Renal disease is one of the most common conditions we see in older cats.
The kidneys themselves may feel small and irregular on physical
examination, the result of scarring over time. But often it’s a
“surprise” finding on routine blood work on a cat who is feeling just
fine; these cases are a mixed blessing. As hard as it is to tell someone
their pet has this condition, the pet benefits greatly from us knowing
early and being able to start early intervention to slow down disease
progression.

Should the finding that tubulointerstitial nephritis might be linked to a virus be of concern to
adopters or cat rescuers?There are a lot of things that cause renal disease in cats, from toxins
to genetics to infections. If it does turn out that some cases can be
tied to a virus, we should be happy — the particular family of virus
referenced in [the study published in Proceedings of the National Academy of Sciences] is one for which vaccines exist in humans
(measles, mumps) and dogs (distemper), so it’s possible that we may be
able to prevent some cases of renal failure in the future. Wouldn’t that
be wonderful?